From c7dc5b5228822d2389e6e441f10169e460bcc67a Mon Sep 17 00:00:00 2001 From: Jakub Kicinski Date: Wed, 12 Nov 2025 19:17:00 -0800 Subject: [PATCH] ipv6: clean up routes when manually removing address with a lifetime When an IPv6 address with a finite lifetime (configured with valid_lft and preferred_lft) is manually deleted, the kernel does not clean up the associated prefix route. This results in orphaned routes (marked "proto kernel") remaining in the routing table even after their corresponding address has been deleted. This is particularly problematic on networks using combination of SLAAC and bridges. 1. Machine comes up and performs RA on eth0. 2. User creates a bridge - does an ip -6 addr flush dev eth0; - adds the eth0 under the bridge. 3. SLAAC happens on br0. Even tho the address has "moved" to br0 there will still be a route pointing to eth0, but eth0 is not usable for IP any more. Reviewed-by: David Ahern Reviewed-by: Ido Schimmel Link: https://patch.msgid.link/20251113031700.3736285-1-kuba@kernel.org Signed-off-by: Jakub Kicinski --- net/ipv6/addrconf.c | 2 +- tools/testing/selftests/net/rtnetlink.sh | 20 ++++++++++++++++++++ 2 files changed, 21 insertions(+), 1 deletion(-) diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c index 40e9c336f6c55..b66217d1b2f82 100644 --- a/net/ipv6/addrconf.c +++ b/net/ipv6/addrconf.c @@ -1324,7 +1324,7 @@ static void ipv6_del_addr(struct inet6_ifaddr *ifp) __in6_ifa_put(ifp); } - if (ifp->flags & IFA_F_PERMANENT && !(ifp->flags & IFA_F_NOPREFIXROUTE)) + if (!(ifp->flags & IFA_F_NOPREFIXROUTE)) action = check_cleanup_prefix_route(ifp, &expires); list_del_rcu(&ifp->if_list); diff --git a/tools/testing/selftests/net/rtnetlink.sh b/tools/testing/selftests/net/rtnetlink.sh index 163a084d525d5..248c2b91fe42b 100755 --- a/tools/testing/selftests/net/rtnetlink.sh +++ b/tools/testing/selftests/net/rtnetlink.sh @@ -8,6 +8,7 @@ ALL_TESTS=" kci_test_polrouting kci_test_route_get kci_test_addrlft + kci_test_addrlft_route_cleanup kci_test_promote_secondaries kci_test_tc kci_test_gre @@ -323,6 +324,25 @@ kci_test_addrlft() end_test "PASS: preferred_lft addresses have expired" } +kci_test_addrlft_route_cleanup() +{ + local ret=0 + local test_addr="2001:db8:99::1/64" + local test_prefix="2001:db8:99::/64" + + run_cmd ip -6 addr add $test_addr dev "$devdummy" valid_lft 300 preferred_lft 300 + run_cmd_grep "$test_prefix proto kernel" ip -6 route show dev "$devdummy" + run_cmd ip -6 addr del $test_addr dev "$devdummy" + run_cmd_grep_fail "$test_prefix" ip -6 route show dev "$devdummy" + + if [ $ret -ne 0 ]; then + end_test "FAIL: route not cleaned up when address with valid_lft deleted" + return 1 + fi + + end_test "PASS: route cleaned up when address with valid_lft deleted" +} + kci_test_promote_secondaries() { run_cmd ifconfig "$devdummy" -- 2.47.3